Presentation on theme: "Health and safety in the prep lab: a step-by-step guide to installing an efficient and cost effective dust collecting and ventilation system Heather C."— Presentation transcript:
Health and safety in the prep lab: a step-by-step guide to installing an efficient and cost effective dust collecting and ventilation system Heather C. Finlayson and Steven D. Sroka, Utah Field House of Natural History State Park Museum, Vernal, UT Thomas Nelsen, Buffalo, NY.
Main Topics Background Evaluation Comparisons and recommendations Design Materials and cost Installation Testing the system Discussion Conclusions
Background Why do we need dust control? Health hazards - Occupational respiratory diseases (radon, silica dust) - Irritation to eyes, ears, nose, skin, throat Risk of dust explosions and fire Equipment damage Impaired visibility Unpleasant odors Public nuisance
Attended First Annual Fossil Preparation and Collections Symposium at PEFO (April, 2008) Presentations by S. Madsen and G. McCullough addressed the following: 1. The importance of promptly addressing safety hazards in the lab, particularly exposure to rock dust. Long term exposure can cause silicosis and lung cancer! 2. Radon gas particles from rocks and fossils can attach to dust and be inhaled. Long term exposure can cause lung cancer!
Measuring radioactivity Radon gas = product of Radium and Uranium decay 1 pCi = 1 trillionth of a Curie 1 pCi/L = 2.2 radioactive disintegrations each minute in 1 L air Ex: 4 pCi/L = 12,672 radioactive disintegrations in 1 L air in 24 hour period Evaluation of work environment at the UFH
Tested for radon in lab and collection storage Results and observations: - our measurements = 1.5 - 1.6 pCi/L - EPA states that there is little short-term risk with readings between 0.6 – 1.9 pCi/L - measurements above 4 pCi/L = EPA action level (4 pCi/L = 200 chest x-rays!)
Radon test recommendations by EPA: - test in closed building conditions - keep test kit away from drafts, fans, blowers - do not test in high humidity (over 55% RH) - do not place near heat - levels fluctuate daily and seasonally, do follow up testing! - test whenever you bring in “hot” rocks and fossils (Last radon test done at UFH in 1997 = 16.8 pCi/L and 32.5 pCi/L, deaccessioned “hot” rocks and minerals to NMBOM)
Performed airflow tests on existing system Results and observations: - a smoke test showed inefficient airflow patterns - thermoanemometer read 90 cfm airflow - accumulation of dust on work surfaces, equipment - rock dust remains suspended
Examined old dust collecting system Results and observations: - 1.5 hp unit designed for saw dust removal, not rock dust - several 90 degree bends in duct work reduced air flow, less efficient - short intake hoses with limited flexibility - 2.5” diameter of intake hoses, decreased volume - location of unit not easily accessible - only 2 blast gates for adjustment of airflow
Comparisons and recommendations Consulted now retired DNM preparator S. Madsen and volunteer D. Gray - DNM’s old system tested in early 90’s by industrial hygienist - results = serious radon and dust issues - they did research, contacted other facilities to compare - DNM got new system in 1996 - larger system, evacs to outside, more remote - 400 cfm at hose – works great! - cost ~ $34,000
Standards ? - no formal standards specific to fossil prep What can we do? - use dust collecting unit specific for rock dust - find some guidelines to design an efficient system - use OSHA and NIOSH recommendations for transport velocities of particulates
OSHA and NIOSH recommendations and guidelines To prevent most industrial dust (granite, silica, limestone, clay, etc.) from settling and blocking ductwork: - minimum 3,500 - 4000 fpm (304 - 400 cfm) at hose opening - branches should enter main duct at low angles = decrease drag - circular ducts instead of rectangular = uniform velocity and distribution
Design Things to consider - budget - size of room - appropriate size/type of unit to create cfm needed (OSHA and NIOSH recommendations) - type, length, diameter of ductwork - city ordinances (noise, dust evac. to outside) - amount, frequency of heavy prep work - # of work stations
UFH specific considerations and needs - low budget - more powerful, affordable unit with easy access - don’t own the building, minimize renovations - temp. occupancy, minimize the cost - have small lab space - chose closed system (no evac.) to avoid nuisance, health hazards to public - put unit in separate room for less noise - drew up preferred design
We called a mechanical engineer! - provided a drawing and system specs - he did the calculations to make sure our specs met industry standards for safe operation - he made some spec adjustments and provided us with a final design Engineering
Comparing length and flex of hose with average airflow (cfm) flexedstraightened Short hose (6 ft.)509 cfm543 cfm Long hose (12 ft.)423 cfm517 cfm Controls: thermoanemometer distance = 4 inches all 4 blast gates were open used the same short hose and long hose for all tests average airflow was taken from 10 readings
Comparing length of and distance from the hose with average airflow (cfm) 2 “4”6” Short hose 1189 cfm509 cfm239 cfm Long hose 1078 cfm423 cfm226 cfm Controls: hoses were flexed for all tests used the same short hose and long hose for all tests all 4 blast gates were open average airflow was taken from 10 readings
Average airflow All 4 gates open 509 cfm 1 short hose gate closed 582 cfm 2 short hose gates closed680 cfm 2 long hose gates closed667 cfm 1 short, 1 long hose gate closed 680 cfm 1 short, 2 long hose gates closed753 cfm 1 long, 2 short hose gates closed766 cfm All 4 gates closed860 cfm Controls: thermoanemometer distance = 4 inches used the same short hose at the station with no blast gates for tests all 6 hoses in system were flexed average airflow was taken from 10 readings Comparing airflow (cfm) with the number of blast gates open
Discussion Interpretation of airflow test results 1. > hose length < airflow 2. > hose flex < airflow 3. > distance < airflow 4. > # blast gates open < airflow 5. Little change in airflow when any combo of two gates are closed 6. Little change in airflow when any combo of three gates are closed 7. Optimal working distance from hose 4”to 5”
Old Unit 1. designed for saw dust 2. 1.5 hp motor, 1200 cfm max. 3. two 2.5 “ diam. inflexible hoses 4. PVC pipes at 90 degree bends 5. avg. air flow 90 cfm 6. Inefficient! 7. did not meet OSHA and NIOSH recommendations New Unit 1. designed for rock particles 2. 10 hp motor, 3200 cfm max. 3. six 4 “ diameter flexible hoses 4. metal ductwork with 45 degree bends 5. avg. airflow exceeds minimum recommendation of 400 cfm 6. Efficient! 7. meets OSHA and NIOSH recommendations Final Comparisons
Important contacts and websites National Institute for Occupational Safety and Health (NIOSH) http://www.cdc.gov/niosh/topics/silica Occupational Safety and Health Administration (OSHA) www.osha.gov/SLTC/silicacrystalline/dust/dust_control_handbook.html Environmental Protection Agency (EPA) www.epa.gov/radon Industrial Hygiene Specialist Consulting Engineer
Conclusions tested well below EPA limits for radon exposure able to install efficient, affordable system new system meets/exceeds OSHA/NIOSH recommendations for dust control project can be used as design template for smaller systems specifically for fossil prep. Don’t take chances! Test for health and safety hazards and don’t wait to take action. This is your life!
Alternate Conclusion: Our new dust collector really sucks!!! Source: NOAA photo library, NOAA central library; OAR/ERL/National Severe Storms Laboratory (NSSL).
We would like to thank the following for their help and support: BHI electrical, BLM of Utah, Craig Brown, Craig Gerber, Dale Gray, Scott Madsen, Utah State Parks and Recreation, Steve Wadsworth at WHW Engineering. Acknowledgements